The long-term objective of this research is to identify those factors which regulate neuropeptide gene expression in the mammalian cerebral cortex, and to define the intracellular mechanisms involved in that regulation. Such studies are fundamental to understanding the role of neuropeptides in a variety of neurological disorders such as dementia and epilepsy. Two peptides found in the cortex and thought to play a role in higher functioning are somatostatin and neuropeptide Y and will be the focus of these studies. The specific aims of this research are to determine: 1) whether specific neurotransmitters are capable of regulating neuropeptide gene expression in the cerebral cortex, 2) the role of the PI- and cAMP-mediated second messenger systems in gene regulation, and 3) whether such regulatory controls are mediated at the level of gene transcription. The experiments will be performed on cultured cerebral cortical neurons from fetal mice. Briefly, the cultures will be exposed to a specific pharmacologic stimulus, such as a neurotransmitter agonist or an agent which stimulates one of the second messenger pathways, and the RNA extracted from the cells several hours later. Changes in somatostatin and neuropeptide Y mRNA levels will be determined (relative to GAD and beta-actin mRNA), and quantified using Northern blot analysis or quantitative polymerase chain reaction (PCR) methodology. Quantitative PCR or transcription run-on assay will be used to determine if changes in mRNA abundance are regulated at the level of gene transcription.